1 maths question

Joe took 10mins to ride a bicycle from bicycle from home to the shore. The

average speed of the whole journey was 600m/min. If his speed in the last 1/3

of his journey was 500m/min,

(a) The distance between a bicycle from bicycle from home to the shore.

600÷10

=60 m

Thus, for the last 1/3 of his journey.

the distance = 60X1/3

= 20 m

the average speed = 600 m/min

∴ the riding time = 20/600
=30min

(b)For the remaining journey

the riding time = (60-30)
= 30min

the distance = 60X2/3
=40m

∴ The speed = 40 /30
= 1 1/3 m/min

(a) The length of his journey
= 600x10
= 6000 (m)

The time he took in the last 1/3 of his journey
= (6000x⅓)÷500
= 2000÷500
= 4 (mins)

(b) The length of his remaining journey
= 6000x(1-⅓)
= 6000x⅔
= 4000 (m)

The time he took in his remaining journey
= 10-4
= 6 (mins)

His speed in the remaining journey
= 4000÷6
= 666⅔ (m/min)
or = 667 (corr. to 3 sig. fig.)